Retractable air brake



July 4, 1950 R. c. HEFFERNAN RETRACTABLE AIR BRAKE 4 Sheets-Sheet 1Filed July 21, 1948 F ii ' INVEN TOR.

BY Rober? C. Neffernan ATTORNEY July 4, 1950 R. c. HEFFERNAN 2,513,867

' RETRACTABLE AIR 13mm Filed July 21, 1948 4 Sheets-Sneet 2 INVENTOR.

BYRaInr? C. Heffcrpdn ATTORNF. Y

July 4, 1950 R, c. HEFFERNAN RETRACTABLE AIR BRAKE- 4 Sheets-Sheet 5Filed July 21, 1948 INVEN TOR.

BY Robert C. Heffernan f3. /My/ ATTORNEY July 4, 1950 R. c. HEFFERNANRETRACTABLE AIR BRAKE 4 Sheets-Sheet 4 Filed July 21, 1948 INVHV TOR.

BY Robgr? C. i-(efferndn m-nmww ATTORNEY Patented July 4, 1950 UNITEDSTATES PATENT OFFICE RETRACTABLE .BRAKE Robert C. Heffernan, St. Albans,N. Y.,, assignor to United Aircraft Corporation, East Hartford, Conn., acorporation of Delaware H Application July 21, 1948, Serial No. 39,988

12 Claims. (Cl. 244-413) ".Thisninvention relates vto improvements in.speed retarding mechanisms of the parachute type. for aircraft and hasparticular reference toan airbrake which is. bothretractable andjettisonable.

It is anobject of this invention to provide a 7 speed retardingdevicefor high performance aircraft by extending a parachute from theair- .plane, the parachute being retractable at the will of the pilot.

It is a furtherzobject. of this invention to provide. a parachute type.airbrake which can be extended and retracted and also can be jettisonedby.,the pilot.

. A still .further object of this'invention is to provide an improvedand simplified mechanism which permits'extension and retraction of aparachute type airbrake and also permits instantaneous release of theparachute from the airplane.

These and;other. objects of the invention will become readily apparentfrom the following de- ....tailed description of the drawings whichindicate one embodiment of this novel concept.

. Inthesedrawings: Fig. 1 is aperspective View of an airplane with theparachute type airbrake in the extended or operative position; 7

Fig. 2 is a longitudinal sectional view of the tail cone section of anairplane showing the airbrake mechanism with the parachute in the stowedposition;

"Fig. 3 is a'perspective view of-thepilot chute inan operative extendedposition, portions of the chute'being broken away to indicate internalstructure;

.i Fig; 4 is a cross sectional side view of the tail 'cone portion ofthe airplane showing the detailed structure of 'the parachute attachingfittings and indicating the engaged position of these fittings 4 duringretraction of the'parachute;

1 Fig. 5 is across sectional side elevation of the v pilot chuteand-indicates the air flow "therethrough;

' Fig. 6' is a cross'sectional rearelevation of the 'cable drumandoperating mechanism which is used'for'extending and retracting theparachute;

*Fig. 7 is a side elevation of the parachute cable *"drum and" indicatesin detail the cable release mechanism; and

*Fig. 8 is a detailed'perspective view'of the aft stopmechanismandin'dicates in detail thestructurelfor releasing the stop mechanismfrom the airplane.

' "-=Referring=to'-Fig. 1,'=the a irbrakemechanism is -=*usuallyu'tilizedon a conventional airplane having fitting 24 and a pilot chute26. .The pilot chute 251s spacedapart from the. apexfitting 24-andattached thereto by an extension cable'28.

j The parachute with... its. attaching fittingsis .normally housedinside out in the. tube 18, as is more clearlyseen inFig. 2. The drum I1is mounted on the aircraftstructure. slightly forwardand in line withthe tube I8 by the bracket 32. The drum ll is actuated by a reversibleelectrio motor 34. through a gear mechanism within the housing 36; thedirection of rotation. of -the motor being controlled. by a cockpitswitch .(not shown).' The cable 38 has its forward end'attached to thedrum I! and. its aite'nd'rotatably connected to the parachute apexfittinglZ l. The extension cable '28 connects the pilot. chute 26 to theapex fitting 24 and ,as seen in Fig. 2 thelpilot chute in its retractedposition forms astreamline closure at the rear of the tail conelBJ Whilethe apex fitting 24 receives the parachute shroud lines at the top ofthe canopy, the other ends of the shroud lines are held by the. shroudcarrier assembly 54 which is slidably mounted in the tube l8. I

The pilot chute'KFig. 3) differs somewhat from the ordinary orconventional pilot chutes in that trio and slidably mounted so as totelescopewithin it consists of a separable frustro-conicalassernblyconsisting of fore andaft sections 5|]v and 52,

respectively. Each of these sections 50 and'52 have integral tubes 54and 56 which are conceneach other. Relativemovement between the sections50 and 52 is limited by means of the slots 58 in the tube'54 and thecooperating'f-tongue guides 68 on the tube 56. A coil spring62nor-'rnally biases the sections and 52 of thepilot chute 26 apart. A cableattachingplat'e fi l, which is rigidly connected to the tub5fiof the aftsection 52, is provided for connecting the'pilot chute to the cabIeZBand in turn to the-apex 'fittin'g' 24.

' In its 'stowed position'the pilot =chute"26' is in aclosed inoperativeposition in the "tail cone-of the'airplane. When the cable 28 is fullydrawn into the tube I 8 'the forward section- 5b of" the the apexfitting 24.

, means of the roller bearin 18.

pilot chute abuts a concave stop member I0, which forms a closurebetween the aft end of tube I8 24 is connected directly to the cable 38which is operated by the drum I1 and is also connected to the pilotchute by thecable28 so that the parachute can be extended andretractedwith its apex first. Therefore, it is readily apparent that the apexfitting 24 has as its primary purpose the control connection forextension and retraction of the parachute and bears only the normalloads of these operations when it is withdrawn by the pilot chute orretracted by the cable 38.

The major air loads during braking are absorbed by the shroud carrierassembly 44 consisting of an annular guide member I4 and a shroudattaching member 16 which has a swivel connection with the guide memberM by means of roller bearings 18 and a lockin disk 80 which is threadedto a forwardly disposed cylindrical portion 82 on the shroud attachingmember 16.

It should be noted at this point that the shroud lines 22 are connectedto the shroud'attaching member I6 by means'of raceways which receive theball swaged fittings at the ends of the shroud cables. Similar fittingsare provided at However, the slots 84 in the apex fitting 24 permitthese swaged ball fittings to rotate sufiiciently when the apex of theparachute is drawn inwardly or extended. The apex fitting 24 in additioncan rotate in relation to the main cable 38 since the latter has a ballswivel connection 86 with the apex fitting 24. The shroud attachingmember 16 can also rotate in relation to the guide member 14 by It istherefore obvious that the shroud lines will not become entangled at anytime since the entire parachute is able to rotate.

The guide member I4 of the shroud carrier assembly is limited in its aftmovement by the annular flange 90 of the closure member I0 whichprotrudes within the aft end of the longitudinal tube I 8. -The closuremember I0 is releasably attached to the tube I8 or a bulkhead so as topermit jettisoning of the shroud carrier assembly and parachute. Theoperation of the release mechanism will be described hereinafter.

As mentioned previously, the drum I1 is operated by reversible electricmotor 34 through a pinion gear I02 (Fig. 6), which in turn drives thespur gear I04, the latter being rigidly attached to the drive shaft I06.The drum I I is also rigidly secured to the shaft I06 by means of boltsI08. The cable 38 is normally wound around the drum I1 and is releasablyattached to the drum by meansof a swaged ball fitting IIO which engagesa bifurcated bracket II2.

As better seen in Fig. 7 the drum I1 and the shaft I06 are securelymounted on the aircraft structure by the bracket 32. The releasemechanism for detaching the cable 38 from the drum II consists of asprocket I20 which has a friction fit on the shaft I06 and carries anintegral fixed plate I22. The sprocket I20 normally rotates with theshaft I06 and the drum I I but it can forcibly be moved in relation tothe shaft the closure member I0.

and the drum. The plate I22 is interconnected with the bifurcatedbracket IIZ by means of a toggled link I24. The bracket H2 is alsopivotally connected at I26 to the drum Ii. An arm I2! is rotatablymounted to the shaft I06 and has its free end pivotally connected to thepawl I30 and the link I32 which is fixed at one end to the pawl I 30.Theiree end of the link I 32 has a cable connection I34 with the bellcrank I36. A pilot operated control cable I38 is connected to the otherend of the bell crank I36 which has a pivot connection I 39 with theairplane structure.

In order to disconnect the cable 38 from the drum I1, the pilot pullsthe cable I38 to the left, as shown by the arrows in Fig. 7. Thismovement rotates the bell crank I36 clockwise which draws the cable I34and'the link I32 downwardly thereby causing the pawl I30 to. rotate andmove against the tension of the spring I40 and engage the teeth on thesprocket I20. Further movement of the pawl will tend to rotate thesprocket I20 on the shaft I06 and the integral plate I22 clockwise andat the same time cause the bifurcated bracket I I2 to turncounterclockwise. The rotation of the bracket II2 causes the ballfitting I I0 to be released from the drum.

The pilots release cable I38 is also connected through a pulley I44(Fig. 8) to the pivot arm I46 on the bulkhead I48 in the rear part ofthe tail cone. The arm I46 has attached thereto a link I50 having anintegral dowel I52 which engages a drilled passage in the lobe I54 on Aspring I56 normally holds the link I50 in a position that permits theengagement of a plurality of fingers I60 0n the closure member I0 withcorresponding lugs I62 on the bulkhead I48. It is then evident that whenthe pilot pulls the cable I38 to release the cable 38 from the drum I!at the same time 1 the link I50 in the aft end of the tail cone will bedrawn downwardly thereby causing the closure member I0 to rotate anddisengage the finture.

Inasmuch as the closure I0 contains an annular flange which acts as astop for the shroud carrier assembly 44, the latter can leave theconfines of the tube I8 and the airplane.

In operation, therefore, should the pilot wish to suddenly reduce thespeed of the airplane he can operate a switch in the cockpit so that themotor 34 rotates the drum IT to pay out the cable 38. Upon initialmovement of the drum I! and the cable 38, the tension on the aft section52 of the pilot chute 26 will be released and the spring 62 within thepilot chute will cause the aft section to move outwardly away from theforward section 50 so that the air stream will flow into the aftersection and create a drag thereon. As the pilot chute is pulled out bythe air pressure, the apex fitting 24 and the canopy 20 will also bewithdrawn from within the tube I8. Once the apex fitting 24 is in theair stream the air loads on the parachute canopy 20 will cause theshroud carrier assembly to slide rearwardly in the tube I8 until thecarrier reaches the annular flange stop 90 on the closure member 10.Therefore, when the parachute is fully extended the shroud carrierassembly will thenbear the full drag load of the parachute andwill tendto retard the speed of the airplane.

amass? When the pilot wishes to retract-the parachute he reverses theelectric motor 34 which rotates the drum 1'! and draws in the cable 38.This in turn causes the apex fitting 24- to retract, thereby turning theparachute inside out and tending to spill the air from the parachutecanopy. When the apex fitting 24 reaches the position shown in Fig. 4,it engages the shroud attaching member 16 on the shroud carrier assembly44 and draws the latter into the tube l8 until the parachute isretracted and the pilot chute is compressed in its closed positionfaired with the tail cone.

In the event that the pilot wishes to jettison the entire parachuteassembly while in its extended position, he pulls the release cable I38(Fig. '7) which causes the pawl I30 to engage the'sprocket I 20 and inturn rotate the bifurcated bracket H2 so as to release the ball fittingH at the forward end of the cable 38. At the same time (Fig. 8) the armI46 and the link I50 will be moved against the tension of the spring I56so as to rotate the closure member 10 and disengage the fingers "if!from the lugs I62 to release the entire rear closure 10 and its integralflange stop 90. Since in the extended position the shroud carrier 44assembly will be abutting the stop 90, it will be pulled free of theairplane from within the tube It and the entire parachute will bejettisoned.

As a result of this invention it is evident that simple mechanism hasbeen provided whereby the speed of high performance aircraft can bereduced considerably at the will of'the' pilotwithin a brief interim oftime. Also, should the pilot findit desirable to continue normal flightafter retarding the airplane by extending the parachute airbrake, he canreadily retract the parachute and stow it within the airplane.

Further as a result of this invention, a parachute type of airbrakemechanism has been provided whereby the parachute can be jettisonedinstantaneously should flight conditions demand such action.

Although only one embodiment of this invention has been shown anddescribed herein, it will be evident that various modifications andchanges can be made withoutdeparting from the scope of this novelconcept.

What is desired by Letters Patent is:

1. In an aircraft, an airbrake comprising a parachute normally housedwithin said aircraft, a cable attached tosaid parachute, mechanismattached to the aircraft and operatively connected to said cable forextending and retracting thesame, means including a spring-ejected pilotchute for initially moving said parachute from its normal position inthe aircraft, and means for jettisoning said cable and parachuteincluding elements cooperating with said mechanism.

2. In an aircraft, an airbrake comprising a parachute normally housedwithin said aircraft, a single cable attached to said parachute,reversible mechanism mounted on the aircraft and operatively connectedto said cable for anchoring, extending and retracting said parachute, apilot chute including spring-biased cooperating sections operativelyconnected to said cable and normally housed in said aircraft and adaptedto initially move said parachute from its position in said aircraft whensaid pilot chute is ejected into the airstream, and pilot operated meansfor ejecting said pilot chute.

3. In an aircraft, an airbrake comprising a parachute normally housedwithin said aircraft,

a cable attached to said parachute, reversible mechanism mounted on theaircraft and operatively connected to said cable for extending andretracting said parachute, a spring-loaded pilot chute operativelyconnected to said cable and normally housed in said aircraft and adaptedto initially move said parachute from its position in said aircraft whensaid pilot chute is ejected into the airstream, pilot operated means forreleasing said pilot chute from its normally housed position, and pilotoperated means for releasing said cable and parachute from saidmechanism.

4'. In an airbrake mechanism for airplanes, a tube mountedlongitudinally in the airplane, a parachute normally housed in said tubehaving shroud lines, an apex connection on said parachute; a winchoperated cable fixed to said connection, a pilot chute spaced apart fromsaid apex connection and attached thereto, a cylindrical shroud carrierslidably mounted in said tube and attached to said shroud lines, saidwinch operated cable controlling the extension and retraction of saidpilot chute and parachute, means for imposing the air loads on saidshroud carrier when said parachute is extended, and stops on said tubefor limiting the aft movement of said carrier.

5. An airbra-ke mechanism'according to claim 4 wherein said shroudcarrier includes a swivel fitting for eliminating shroud entanglementdue to spinning of the parachute in the extended posi-tion.

"6; In an airplane airbrake mechanism, a tube mounted along thelongitudinal axis of the airplane, a reversible wind-lass mountedforward of said tube-and having a cable extended aft therefrom, aparachute housed in said tube having its apex attached to said cable, apilot chute at the aft end of said tube, an extension of said cableconnecting said apex to said pilot chute and normally maintaining saidpilot chute in an inoperative position at the end of said tube, springloadingmeans for constantly urging said pilot chute rearwardly away fromthe end of said tube into the air stream, a cylindrical shroud carrierslidablymounted in said tube and having a centralaperture for permittingsaid cable to pass therethrough to said apex, stop meansdetachablymounted to the aft end of said tube for limiting the aftmovement of said shroud carrier, pil'otoperated means for extending andretracting said parachute by operation of said Windlass, and-means forjettisoning said parachute including'a'single control for releasing saidcable connection at said Windlass and disconnectin said 'stcp'means fromsaid tube.- I

7. In an airplane, a retractable'airbrake mechanism comprising alongitudinal tube terminating inthe aft end of the airplane, a parachutenormally housed in said tube, said parachute having an apex fitting anda shroud carrier, said shroud carrier having a central opening and beingslidably mounted within said tube forward of said apex fitting, areversible Windlass mounted to said airplane and disposed forward ofsaid tube, a cable releasably connecting said Windlass to said apexfitting and passing through said central opening, a concave closurereleasably attached to the aft end of said airplane and having anannular flange protruding within the end of said tube, said flangeforming a stop for limiting the aft movement of said shroud carrier, apilot chute spaced from said apex fitting and attached thereto, saidpilot chute normally held against spring tension in an inoperativeposition by saidlwindlass and adapted to be faired withinsaid concaveclosure, and a single pilot operated control for jettisoning saidparachute from an extended position including means for releasing saidcable from said Windlass and disabling said stop. r

"8'. In a mechanism for jettisoning a retracte able airbrake'parachutefor airplanes, a reversiblewindlass, a cable connecting the apex of saidparachute to said Windlass, said cable being detachably connected tosaid Windlass by a ball fitting engaging a rotatable bifurcated bracketon said Windlass, a longitudinal tube normally housing said parachuteand having a parachute shroud carrier slidably mounted therein, stopmeans onthe aft end of said tube for limiting the aft movement of saidshroud carrier, said stop means comprising an annular flange protrudingforward within the end of said tube and held in position by a pluralityof spaced locking lugs on the outer periphery of said tube, and controlmeans for detaching said cable from said Windlass and said stop meansfrom said tube including a single release mechanism for rotating saidbifurcated bracket to disengage said fitting and for rotating saidannular flange to disengage said locking lugs.

9. An airbrake mechanism for airplanes comprising a tube mountedlongitudinally in the tail cone of the airplane and having its aft endterminating slightly forward of the trailing edge of said cone, aconcave closure member releasably attached to the airplane andconnecting the aft end of said tube with said trailing edge,

said closure having an annular flange protruding within the end of saidtube, a parachute normally housed in said tube, a cylindrical shroudcarrier slidably mounted within said tube and having a swivel connectionwith the shroud first, a pilot chute spaced from and attached tosaid'apex fitting, said pilot chute being normally stowed in aninoperative position abutting said closure member, a spring urging saidpilot chute away from said closure member and tending to move said pilotchute into the-air streamin response 'to unwinding ofsaid cable fromsaid windlass, and a pilotoperatedcontrol for jettisoning said parachuteand shroud carrier from the airplane including means for releasing saidcable from said drum and said closure member from said airplane.

=10. In'a pilot chute mechanism for-use with a retractable parachuteairbrake for airplanes, a separable frustro-conical chute having foreand aft sections faired intothe tail section of an airplane; said aftsection having a central openi-ng andsaid fore section normally abuttingsaid aft section and forming a closure for said opening, -said sectionbeing held in the aforesaid abutting position by a pilot operatedretracting mechanism, and means for exposing said opening to the airstream to cause a drag on said aft section including resilient means forseparating said sections responsive to release of said retractingmechanism.

11. In anairbrake mechanism for airplanes, a tube'mounted longitudinallyin the airplane, a parachute normallyhoused in said tube having shroudlines, an apex connection on said parachute, a winch operated cablefixed to said connection, a pilot chute spaced apart from said apexconnection and attached thereto, a cylindrical shroud carrier slidablymounted in said tube and attached to said shroud lines, said winchoperated cable controlling the extension and retraction of said pilotchute and parachute, and stop means on said tube for limiting the aftmovement of said carrier.

7 12. In an airbrake mechanism for airplanes, a tube mountedlongitudinally in the airplane, a parachute normally housed in said tubehaving shroud lines, an apex connection on said parachute, a winchoperated cable fixed to said connection, a pilot chute spaced apart fromsaid apex connection and attached thereto, a cylindrical shroud carrierslidably mounted in said tube and attachedto said shroud lines, saidwinch operated cable controlling the extension and retraction of saidpilot chuteand parachute, means for imposing air loads on said shroudcarrier when said parachute is extended, and means for transferring saidloads from said carrier to the structure of said airplane.

ROBERT C. HEFFERNAN.

REFERENCES CITED Thefollowing references are of record in the file ofthis patent:

UNITED STATES PATENTS

